Anti-fog coating composition, process, and article

ABSTRACT

An anti-fog coating composition comprises a silicone polymer or oligomer, a water dispersible polyurethane polymer or oligomer, and water. A process for forming an anti-fog film comprises applying the anti-fog coating composition to a substrate and coalescing the silicone and polyurethane compounds to form the film. In another embodiment, the process for forming the anti-fog film comprises applying the components of the anti-fog coating composition to a substrate and crosslinking the components to form the anti-fog film. The components generally include a polyol, an isocyanate, a catalyst, and a silicone polymer or oligomer.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is a divisional of U.S. patent application Ser.No. 10/062,646 filed on Jan. 31, 2002, which is incorporated byreference herein.

BACKGROUND OF THE INVENTION

[0002] The present disclosure relates to coating compositions, and moreparticularly, to coating compositions that form films exhibitinganti-fog and/or anti-condensation properties.

[0003] There are numerous instances in which optically clear articleswould be enhanced if they were resistant to the formation of a fog on asurface of the article, for example, in window applications such as forgreenhouses.

[0004] In general, fog and condensation formation occur under conditionsof high humidity and high temperature or at interfacial boundaries wherethere is a large temperature and humidity difference. Coatings thatreduce the tendency for surfaces to “fog up” have been reported. Theseso-called anti-fog coatings improve the wettability of a surface byallowing a thin layer of water film to form on the surface instead ofdiscrete droplets. Known anti-fog coatings include, for example,coatings using ammonium soap, such as mixtures of an alkyl ammoniumcarboxylates with a surface active agent, for example, a sulfated orsulfonated fatty material; salts of sulfated alkyl aryloxypolyalkoxyalcohol; or alkylbenzene sulfonates. Other common anti-fog coatingcompositions use colloidal silica to provide water resistance. However,colloidal silica coating compositions generally have a high solventcontent and are generally less effective for controlling condensation.Other common anti-fog compositions require chemical crosslinking to forma cohesive film. Although less solvent is used, the chemicalcrosslinking can significantly affect film properties. A highlycrosslinked coating can cause the coated film to be brittle whereas lowcrosslinking can result in chalking, i.e., a powdery film that degradesor disperses upon contact with an aqueous solution.

[0005] Although the above noted coating formulations have addressed someof the problems in the field, none provides a total solution. Most ofthe formulations have low moisture absorptivity, long moisture releasetime, and/or poor water and solvent resistance. For example,water-soluble silicone resins synthesized from hydrophilic functionalgroup-bearing silane compounds generally have poor water resistance,inadequate film hardness and poor weathering resistance. Some of theseformulations also have inefficient fabrication processes, e.g., a longcoat curing time. To be useful in most commercial applications, theanti-fog coating should possess high clarity, possess a long shelf lifeprior to coating, exhibit impact resistance properties suitable for theintended application, be able to absorb and release moisturesimultaneously, and be able to resist water and conventional organicsolvents, such as alcohols, alkylbenzenes (e.g., toluene), glycol ethers(e.g., propylene glycol monomethyl ether), and alkyl ketones (e.g.,methyl ethyl ketone).

SUMMARY OF THE INVENTION

[0006] Disclosed herein is an anti-fog coating composition comprising asilicone compound, a water dispersible polyurethane compound, and water.

[0007] A process for forming an anti-fog film on a substrate comprisesapplying an aqueous coating composition to the substrate, wherein theaqueous coating composition comprises a silicone compound, a waterdispersible polyurethane compound, and water; and coalescing thesilicone compound and polyurethane compound to form a film.

[0008] In another embodiment, a process for forming an anti-fog filmcomprises applying a coating composition to a substrate, wherein thecoating composition comprises a silicone compound, an isocyanate, apolyol and a catalyst; and crosslinking the coating composition to forma film, wherein crosslinking comprises heating the substrate to atemperature and for a time effective to form the film.

[0009] A glass or plastic article having an anti-fogging surfacecomprises a glass or plastic substrate and an anti-fog coating disposedon at least one surface of the substrate, the anti-fog coatingcomprising a silicone compound, a water dispersible polyurethanecompound, and water.

[0010] In another embodiment, glass or plastic article having ananti-fogging surface comprises a glass or plastic substrate; and ananti-fog coating disposed on at least one surface of the substrate, theanti-fog coating comprising a crosslinked film formed from a silicone,an isocyanate, a polyol and a catalyst.

[0011] These and other features will be apparent from the followingdetailed description.

DETAILED DESCRIPTION OF THE INVENTION

[0012] An anti-fog, water based coating composition is obtained bycombining a silicone compound having a hydrophilic functional group witha water dispersible polyurethane compound. A film formed from theanti-fog coating composition is primarily formed by coalescence, aprocess that causes the silicone and polyurethane compounds to flow intoeach other and form a continuous film. Advantageously, the resultingfilms exhibit, among others, low solvent retention, durability, andflexibility.

[0013] In general, a formulation of the coating composition comprises asilicone polymer or oligomer, a water dispersible polyurethane polymeror oligomer, and water. The silicone polymer or oligomer is about 0.1 toabout 20 parts by weight of the formulation, with about 1 to about 10parts by weight more preferred, and with about 1 to about 5 parts byweight even more preferred. The water dispersible polyurethane polymeror oligomer is about 5 to about 50 parts by weight of the formulation,with about 10 to about 40 parts by weight more preferred, and with about20 to about 30 parts even more preferred. The remainder of theformulation comprises an aqueous solvent, i.e., water and an optionalco-solvent miscible with water. Any co-solvent included in theformulation is preferably about 1 to about 10 parts per weight and morepreferably, about 5 to 10 parts by weight of the formulation. The sum ofthe weights of the compounds preferably totals 100 parts by weight. Ofcourse, other compounds (such as a UV absorbers, light stabilizers,pigments, dyes, etc.) may be added to or omitted from a formulation, inwhich case the relative amounts of each of the compounds would beadjusted accordingly to total 100 parts by weight, as would be apparentto one skilled in the art in view of this disclosure.

[0014] The term silicone as used herein includes polymers or oligomersof organosiloxanes (and moieties derived therefrom) wherein each organogroup is independently selected from the group consisting of alkylgroups such as C₁ to C₁₂ alkyl groups, for example. At least one or moreof the organo groups contain one or more hydrophilic functional groups.Any hydrophilic functional group may be used. Examples of suitablehydrophilic functional groups include —CO₂H; —OH; —NH; oxyethylenesegments, other nitrogen containing organic functional groups, —SH;ester, urethane, and isocyanate groups. In a preferred embodiment,functional group is a weak acid group. It is preferred that the siliconepolymer or oligomer does not include strong acids such as sulfonic acidfunctional groups. The presence of strong acids such as the sulfonicacid groups in the silicone polymer or oligomer (and the amines that arecommonly used to neutralize the acid) can degrade the polymer filmformed from the coating composition, cause discoloration, result in poorweathering performance, or result in a film exhibiting high watersensitivity. The preferred functional groups provide room temperaturecuring sites for film coalescence, act as dispersing aids by loweringthe surface energy of the aqueous dispersion, and/or lower the minimumfilm forming temperature.

[0015] Preferred silicone resins are organosiloxanes, free from sulfonicacid functional groups, having the general formula:

M_(a) M′_(b)D_(c)D′_(d)T_(e)T′_(f)Q_(g),

[0016] wherein the subscripts a, c, d, e, f, and g are zero or apositive integer, subject to the limitation that the sum of thesubscripts b, d, and f is one or greater; M has the formula: R¹ ₃SiO_(1/2), where each R¹ is independently a monovalent hydrocarbonradical having from one to forty carbon atoms; M′ has the formula: R²_(3−h) R³ _(h) SiO_(1/2), wherein each R² and R³ are independentlymonovalent hydrocarbon radicals having from one to forty carbon atoms,and the subscript h is 1, 2, or 3; D has the formula: R⁴ ₂ SiO_(2/2),wherein each R⁴ is independently a monovalent hydrocarbon radical havingfrom one to forty carbon atoms; D′ has the formula: R⁵ _(2-i)R⁶_(i)SiO_(2/2), wherein each of R⁵ and R⁶ is independently a monovalenthydrocarbon radical having from one to forty carbon atoms, and thesubscript i is 1 or 2; T has the formula: R⁷SiO_(3/2), wherein each R⁷is a monovalent hydrocarbon radical having from one to forty carbonatoms; T′ has the formula: R⁸SiO_(3/2), wherein R⁸ is a monovalenthydrocarbon radical having from one to forty carbon atoms; and Q has theformula: SiO_(4/2).

[0017] More preferably, the silicone is an ionic or nonionic siloxanealkoxylate having the general formula:

[0018] wherein each of R⁹⁻¹⁷ are independently a monovalent hydrocarbonradical, R¹⁸ is of the general formula: R¹⁹-Z-(C_(m)H_((2m-1))R²⁰O)_(j)(C_(n)H_(2n)O)_(k) R²¹, m and n are integers greater than or equal to 0;j and k are integers greater than or equal to 0, subject to the provisothat the sum of j+k is greater than or equal to 1; Z is —O—, —S—, —CO—,—NH—, or —NH₂—; R¹⁹ is a divalent hydrocarbylene radical, R²⁰ and R²¹are independently hydrogen, alkyl, hydroxyalkyl, amino, amido,amineoxide, cyano, isocyano, aryl, arylene, carboxy, alkoxy, halogen,haloalkyl, haloalkoxy, sulfo, sulfamo, phosphono, salts thereof, or acombination comprising at least one of the foregoing, and the like; andwherein x and y are integers greater than or equal to 0, subject to theproviso that x+y is greater than or equal to 1.

[0019] Preferred silicone resins are polydimethylsiloxanes. Exemplarypolydimethylsiloxanes include, but are not limited to,poly[dimethylsiloxane-co-methyl(3-hydroxypropyl)siloxane]-graft-poly(ethyleneglycol) methyl ether,poly[dimethylsiloxane-co-[3-[2-(2-hydroxyethoxy)ethoxy]propyl]methylsiloxane,poly[dimethylsiloxane-co-(3-aminopropyl)methylsiloxane],poly[dimethylsiloxane-co-methyl(3-hydroxypropyl)siloxane]-graftpoly(ethylene/propylene glycol) methyl ether,poly[dimethylsiloxane-co-methyl(3-hydroxypropyl)siloxane]-graft-tetrakis(1,2-butyleneglycol), poly(dimethylsiloxane-co-alkylmethylsiloxane),poly[dimethylsiloxane-co-methyl(stearoyloxyalkyl)siloxane],poly[dimethylsiloxane-co-methyl(3-hydroxypropyl)siloxane]-graft-poly(ethylene/propyleneglycol),poly[dimethylsiloxane-co-methyl(3-hydroxypropyl)siloxane]-graft-poly(ethyleneglycol) [3-(trimethylammonio)propyl chloride,poly[dimethylsiloxane-co-methyl(3-hydroxypropyl)siloxane]graft-poly(ethyleneglycol) 3-aminopropyl ether,poly[dimethylsiloxane-co-methyl(3,3,3-trifluoropropyl)siloxane],poly(dimethylsiloxane bis[[3-[(2-aminoethyl)amino]propyl]dimethoxysilyl]ether, and poly(dimethylsiloxane) ethoxylate/propoxylated.

[0020] The term water dispersible polyurethane, generally refers to apolymeric or oligomeric material, the backbone of which comprises amultiplicity of urethane linkages, —O—CO—NH—, and may also contain oneor more urea linkages: —NH—CO—NH—, and may also contain one or morethiocarbamate linkages: —S—CO—NH— and combinations thereof.

[0021] The water dispersible polyurethanes are preferably formed fromcompositions comprising an organic isocyanate component reactive with anactive hydrogen-containing component(s), and a catalyst.

[0022] The organic isocyanate components used in the preparation of thewater dispersible polyurethane preferably are those having the generalformula:

Q(NCO)_(i)

[0023] wherein i is an integer of two or more and Q is an organicradical having a valence of i, wherein i is greater than 2. Q can be asubstituted or unsubstituted hydrocarbon group (i.e., an alkylene or anarylene group). Q can be a group having the formula Q¹-Z-Q¹ wherein Q¹is an alkylene or arylene group and Z is —O—, —O-Q¹-S, —C(O)—, —S—,—S-Q¹-S—, —SO— or —SO₂—. Examples of such compounds includehexamethylene diisocyanate, 1,8-diisocyanato-p-methane, xylyldiisocyanate, diisocyanatocyclohexane, phenylene diisocyanates, tolylenediisocyanates, including 2,4-tolylene diisocyanate, 2,6-tolylenediisocyanate, and crude tolylene diisocyanate,bis(4-isocyanatophenyl)methane, chlorophenylene diisocyanates,diphenylmethane-4,4′-diisocyanate (also known as 4,4′-diphenyl methanediisocyanate, or MDI) and adducts thereof, naphthalene-1,5-diisocyanate,triphenylmethane-4,4′,4″-triisocyanate,isopropylbenzene-alpha-4-diisocyanate, and polymeric isocyanates such aspolymethylene polyphenylisocyanate.

[0024] The active hydrogen-containing component includespolyhydroxyl-containing compounds, such as hydroxyl-terminatedpolyhydrocarbons (U.S. Pat. No. 2,877,212); hydroxyl-terminatedpolyformals (U.S. Pat. No. 2,870,097); fatty acid triglycerides (U.S.Pat. Nos. 2,833,730 and 2,878,601); hydroxyl-terminated polyesters (U.S.Pat. Nos. 2,698,838, 2,921,915, 2,591,884, 2,866,762, 2,850,476,2,602,783, 2,729,618, 2,779,689, 2,811,493, and 2,621,166);hydroxymethyl-terminated perfluoromethylenes (U.S. Pat. Nos. 2,911,390and 2,902,473); polyalkylene ether glycols (U.S. Pat. No. 2,808,391;British Pat. No. 733,624); polyalkylene ether glycols (U.S. Pat. No.2,808,391; British Pat. No. 733,624); polyalkylenearylene ether glycols(U.S. Pat. No. 2,808,391); polycarbonate polyol (U.S. Pat. Nos.6,087,051 and 6,057,034) and polyalkylene ether triols (U.S. Pat. No.2,866,774).

[0025] Preferred polyhydroxyl-containing materials are the polycarbonatepolyols and polyether polyols. The polycarbonate polyols may be, forexample, polycarbonatediols which are obtainable by a reaction of ashort chain dialkylcarbonate and a component selected fromaforementioned polyether polyols, polyesterpolyols, and diol componentssuch as 2-methylpropanediol, dipropylene glycol, 1,4-butanediol,1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol,1,5-octanediol, 1,4-bis-(hydroxymethyl)cyclohexane, and the like. Theshort chain dialkylcarbonate may be C₁₋₄ alkylcarbonates such as, forexample, dimethylcarbonate and diethylecarbonate. Examples ofcommercially available polycarbonate diol may be DESMOPHENE 2020E(manufactured by Sumitomo Bayer Co., Ltd.), DN-980, DN-982 and DN-983(manufactured by Japan Polyurethane Industry Co., LTD).

[0026] Polyether polyols may be obtained by the chemical addition ofalkylene oxides, such as ethylene oxide, propylene oxide and mixturesthereof, to water or polyhydric organic compounds, such as ethyleneglycol, propylene glycol, trimethylene glycol, 1,2-butylene glycol,1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,2-hexylene glycol,1,10-decanediol, 1,2-cyclohexanediol, 2-butene-1,4-diol,3-cyclohexene-1,1-dimethanol, 4-methyl-3-cyclohexene-1,1-dimethanol,3-methylene-1,5-pentanediol, diethylene glycol,(2-hydroxyethoxy)-1-propanol, 4-(2-hydroxyethoxy)-1-butanol,5-(2-hydroxypropoxy)-1-pentanol, 1-(2-hydroxymethoxy)-2-hexanol,1-(2-hydroxypropoxy)-2-octanol, 3-allyloxy-1,5-pentanediol,2-allyloxymethyl-2-methyl-1,3-propanediol,[4,4-pentyloxy)-methyl]-1,3-propanediol,3-(o-propenylphenoxy)-1,2-propanediol,2,2′-diisopropylidenebis(p-phenyleneoxy)diethanol, glycerol,1,2,6-hexanetriol, 1,1,1-trimethylolethane, 1,1,1-trimethylolpropane,3-(2-hydroxyethoxy)-1,2-propanediol,3-(2-hydroxypropoxy)-1,2-propanediol,2,4-dimethyl-2-(2-hydroxyethoxy)-methylpentanediol-1,5;1,1,1-tris[2-hydroxyethoxy) methyl]-ethane,1,1,1-tris[2-hydroxypropoxy)-methyl] propane, diethylene glycol,dipropylene glycol, pentaerythritol, sorbitol, sucrose, lactose,alpha-methylglucoside, alpha-hydroxyalkylglucoside, novolac resins,phosphoric acid, benzenephosphoric acid, polyphosphoric acids such astripolyphosphoric acid and tetrapolyphosphoric acid, ternarycondensation products, and the like. The alkylene oxides employed inproducing polyoxyalkylene polyols normally have from 2 to 4 carbonatoms. Propylene oxide and mixtures or propylene oxide with ethyleneoxide are preferred. The polyols listed above can be used per se as theactive hydrogen compound.

[0027] A preferred class of polyether polyols is generally representedby the following formula:

R[(OCH_(n)H_(2n))_(z)OH]_(a)

[0028] wherein R is hydrogen or a polyvalent hydrocarbon radical; a isan integer (i.e., 1 or 2 to 6 to 8) equal to the valence of R, n in eachoccurrence is an integer from 2 to 4 inclusive (preferably 3) and z ineach occurrence is an integer having a value of from 2 to about 200,preferably from 15 to about 100.

[0029] Additional active hydrogen-containing compounds are the polymersof cyclic esters. The preparation of cyclic ester polymers from at leastone cyclic ester monomer is well documented in the patent literature asexemplified by U.S. Pat. Nos. 3,021,309 through 3,021,317; 3,169,945;and 2,962,524. Suitable cyclic ester monomers include, but are notlimited to, delta-valerolactone; epsilon-caprolactone;zeta-enantholactone; the monoalkyl-valerolactones, e.g., themonomethyl-, monoethyl-, and monohexyl-valerolactones.

[0030] Cyclic ester/alkylene oxide copolymers can also be prepared byreacting a mixture comprising cyclic ester and alkylene oxide monomers,an interfacial agent such as a solid, relatively high molecular weightpoly(vinylstearate) or lauryl methacrylate/vinyl chloride copolymer(reduced viscosity in cyclohexanone at 30° C. from about 0.3 to about1.0), in the presence of an inert normally-liquid saturated aliphatichydrocarbon vehicle such as heptane and phosphorus pentafluoride as thecatalyst therefore, at an elevated temperature, e.g., about 80° C.

[0031] Another type of active hydrogen-containing materials are thepolymer polyol compositions obtained by polymerizing ethylenicallyunsaturated monomers in a polyol as described in U.S. Pat. No.3,383,351. Suitable monomers for producing such compositions includeacrylonitrile, vinyl chloride, styrene, butadiene, vinylidene chlorideand other ethylenically unsaturated monomers as identified and describedin the above-mentioned U.S. patent. The polymer polyol compositions cancontain from 1 to about 70 weight percent (wt %), preferably about 5 toabout 50 wt %, and most preferably about 10 to about 40 wt % monomerpolymerized in the polyol. Such compositions are conveniently preparedby polymerizing the monomers in the selected polyol at a temperature ofabout 40° C. to about 150° C. in the presence of a free radicalpolymerization catalyst such as peroxides, persulfates, percarbonate,perborates and azo compounds.

[0032] The exact polyol or polyols employed depends upon the desiredcharacteristics of the polyurethane. In particular, variation in thepolyol component and the structure of the amine in the chain extensionprocess for forming the polyurethane can yield a wide range of moduliand toughness.

[0033] Catalysts include various inorganic metal compounds and metalcompounds that include certain organic groups. Metal acetyl acetonatesare preferred, based on metals such as aluminum, barium, cadmium,calcium, cerium (III), chromium (III), cobalt (II), cobalt (III), copper(II), indium, iron (II), lanthanum, lead (II), manganese (II), manganese(III), neodymium, nickel (II), palladium (II), potassium, samarium,sodium, terbium, titanium, vanadium, yttrium, zinc and zirconium. Acommon catalyst is bis(2,4-pentanedionate) nickel (II) (also known asnickel acetylacetonate or diacetylacetonate nickel) and derivativesthereof such as diacetonitrilediacetylacetonato nickel,diphenylnitrilediacetylacetonato nickel, bis(triphenylphosphine)diacetylacetylacetonato nickel, and the like.

[0034] Optionally, the water dispersible polyurethane may containadditional water dispersible components such as an acrylate, polyesteror the like. Alternatively, these moieties may be chemically attached tothe polyurethane to prevent phase separation or other film coatingdefect.

[0035] Suitable commercially available water dispersible polyurethanesinclude BAYHYDROL 121 available from Bayer Corporation, WITCOBONDavailable from Witco Corporation, Q-THANE available from KJ Quinn, Inc.,K-FLEX available from King Industries, and FLEXANE available from theAir Products and Chemicals, Inc.

[0036] Depending on the particular silicone polymer or oligomer, the useof the co-solvent may be employed. Suitable co-solvents include N-methylpyrrolidone, glycol ethers, isopropanol and combinations comprising atleast one of the foregoing co-solvents. In a preferred embodiment, theco-solvent is N-methyl pyrrolidone.

[0037] The coating compositions can additionally contain other additivesand adjuvants, such as adherence modulators (linear silicone polymers orresins bearing vinyl, epoxy, vinyl ether, alcohol and the likefunctional groups), pigments (for example titanium dioxide and ironoxide), photosensitizing agents, fillers (alumina trihydrate, silica,talc, calcium carbonate, clay, and the like), dyes, fungicidal,bactericidal and anti-microbial agents, antistatic agents, particulateswhich control the friction or surface contact areas, defoamers, buffersto control pH of the coating compositions, corrosion inhibitors and thelike. Use of UV absorbers or light stabilizers, such as hindered aminelight stabilizers, can be used to further impart UV resistance. Otheradditives may also be used, if desired.

[0038] The formulations are prepared by admixing the componentstogether. Preferably, the formulations are prepared by adding a dilutesilicone polymer or oligomer solution or dispersion to the waterdispersible polyurethane dispersion.

[0039] Water and/or additional co-solvent is then added to achieve thedesired solids content and viscosity. The additives and adjuvants, ifpresent, may be added at any stage of the mixing process.

[0040] In another embodiment, the anti-fog coating composition isprepared by admixing the silicone polymer or oligomer with thecomponents that form the water dispersible polyurethane, i.e., polyol,isocyanate and catalyst in a suitable solvent, coating a solution of theadmixture, and curing the coated formulation to form a crosslinked film.

[0041] In another embodiment, the anti-fog coating formulation isprepared by admixing the silicone polymer or oligomer with thecomponents that form the water dispersible polyurethane, i.e., polyol,isocyanate and catalyst, coating a substrate with the dispersion, andcuring the coated formulation to form a coalesced film. In thisembodiment, the silicone polymer or oligomer preferably comprises afunctional group that is preferably a weak acid, e.g., a carboxylic acidmoiety. In this manner, the silicone component is chemically attached tothe polyurethane and the resulting film is formed by coalescence.Advantageously, physical loss due of the silicone compound due toevaporation or the like is prevented.

[0042] Any number of coating methods may be employed to coat theanti-fog coating composition onto a surface of a desired substrate, forexample, roller coating, wire-bar coating, dip coating, extrusioncoating, air knife coating, curtain coating, slide coating, bladecoating, doctor coating, or gravure coating.

[0043] Preferably, the coated film is heat treated to form the coalescedor crosslinked polymeric network. Suitable temperatures for forming thecoalesced or crosslinked polymeric network in the coating compositionare preferably at about room temperature to about 150° C., with 50° C.to 130° C. more preferred and with 100° C. to about 120° C. even morepreferred. The duration of heating should be effective to form the filmand is preferably about 2 to about 60 minutes. These temperatures andtimes are not intended to be limiting, however, since those of ordinaryskill in the art will recognize that the temperatures and times utilizedwill vary according to the actual physical characteristics of the formedcoating (e.g., coating layer thickness, additives, ratios of components,etc.). Even so, as a general rule, the higher the treating temperatureutilized, the more quickly the coalesced polymeric network forms in thecoating composition.

[0044] The coat weight of the anti-fog coating is not particularlyrestricted, but should generally be in the range from about 0.5 g/m² toabout 15 g/m² depending on the film thickness. For most applications,the thickness of the coating is preferably at about 0.5 to about 15micrometers.

[0045] The coatings are typically used to provide anti-fog properties toa surface of a substrate, wherein the substrate comprises a plastic orglass material. Suitable plastic materials include polyester, celluloseesters, polycarbonate, polystyrene, poly(vinyl acetate), polyolefins,and the like. The substrate thickness is not particularly restricted,and usually depends entirely upon the application. Typical thicknessesare about 0.005 inches to about 0.5 inches for monolithic structures,and about 4 millimeter to about 16 millimeters for structuredsubstrates. The substrate may be pretreated to enhance adhesion of theanti-fog coating.

[0046] The following examples illustrate the disclosure withoutlimitation. All parts are given by weight unless otherwise indicated.

EXAMPLE 1

[0047] An anti-fog coating formulation is as follows. Component Amount(grams) Polyol (RUCOFLEX S-1028) 20.0 Polyisocyanate (DESMODUR N-75)10.0 Silicone 4.0 (poly[dimethylsiloxane-co-[3-[2-(hydroxyethoxy)ethoxy] propyl]methyl-siloxane) Catalyst (dibutylindilaurate) 0.05 Diacetone alcohol 6.0 t-Butanol 60.0

[0048] The formulation was applied to a polycarbonate substrate anddried in an oven at an elevated temperature forming a crosslinked film.The anti-fog film formed on the polycarbonate substrate exhibitedimproved flexibility, e.g., elongation was greater than 50%.

EXAMPLE 2

[0049] An anti-fog coating formulation is as follows. Component Amount(grams) Polypropylene glycol diol (Mol. Wt. ˜1000, ARCO) 22.5 gHydrogenated diphenyl methane diisocyanate  9.8 g Dimethylol propionicacid 1.25 g Diethylene triamine 0.63 g Triethylamine 0.92 gN-methyl-pyrrolidinone 16.5 g Poly[dimethylsiloxane-co-  4.0 gmethyl(3-hydroxypropyl)siloxane-graft- [poly(ethylene glycol) methylether]-[poly(ethylene glycol) Dibutyltin dilaurate 0.05 g Water 44.4 g

[0050] In this example, the silicone compound is chemically attached tothe polyurethane during formation of an aqueous dispersion.Polypropylene glycol diol, dimethylol propionic acid (dissolved in ⅓ ofthe N-methyl-pyrrolidinone), and dibutyltin dilaurate are charged into areactor with temperature control under a nitrogen environment at atemperature about 80° C. Hydrogenated diphenyl methane diisocyanate isadded slowly to the reactor and the reaction is continued for 3 hoursuntil the theoretical NCO % is reached. The reaction mixture is thencooled to 60° C. Triethylamine is then added to neutralize the acidfunctionalities. Water is then added with vigorous agitation to form thedispersion. To this a diethylene triamine/N-methyl-pyrrolidinone/watersolution is added to complete chain extension and the reaction is keptfor 2 hours. The resulting polyurethane dispersion had a solids contentof about 35 to about 40-weight %.

[0051] The dispersion is then applied to a substrate and dried at anelevated temperature in an oven. The resulting film is formed bycoalescence and exhibited anti-fog properties.

EXAMPLE 3

[0052] An anti-fog coating formulation is as follows. Component Amount(grams) Silicone compound 2 (poly[dimethylsiloxane-co-[3 -[2-(hydroxyethoxy)ethoxy] propyl]methyl-siloxane) Polyurethane AqueousDispersion 58 (BAYHYDROL 121) UV Absorber 1.5 (TINUVIN 400, CibaSpecialty Chemicals) UV Light Stabilizer 0.05 (UVINUL 3058, BASF Corp.)Water 38.45

[0053] The coating composition of Example 2 was applied at a thicknessof about 8 micrometers to a polycarbonate film and dried at 130° C. for30 minutes. The properties of the coated substrate were evaluated andare summarized in Table 1. TABLE 1 TEST RESULTS Fogging Time Greaterthan 60 seconds Sheeting Performance No bead or droplet formation XenonArc YI ≦ about 2, no delamination after 3000 hours acceleratedweathering QUVB (FS-40) YI ≦ about 6, no delamination after 3000 hoursaccelerated weathering Impact Resistance ≧about 160 to about 200 pounds

[0054] Fogging time is expressed as the time it takes to visually form afog on a surface of the coating by placing the coating 1 inch above avessel of water (coating surface facing the water). The water was heatedto a temperature of 55° C. No fogging was observed after 60 seconds ofexposure.

[0055] Sheeting performance is a qualitative measure of theanti-condensation properties commonly used for measuring theapplicability of the product for greenhouse window applications. Astream of water is applied to the coated surface at a 45° angle and itsflow pattern is observed. If the water flow forms a continuous path, theperformance is considered acceptable. In contrast, if the water forms abead or droplets upon the surface, the performance is consideredunacceptable. Acceptable sheeting performance was observed for thecoated substrate.

[0056] The weatherability testing included exposing the coated surfaceof the substrate to a xenon arc light source or a QUVB light source. AnAtlas Ci35 Xenon Arc weatherometer was employed for exposing the coatingto the xenon light source and included a borosilicate glass filterelement for filtering wavelengths less than about 290 nanometers. Theweathering cycle included a 160-minute exposure at 70° C. and 50%relative humidity followed by a 5 minute cool down in the dark and a15-minute water spray. The average irradiance was 0.77-watts/squaremeter at 340 nanometers. The weathering cycle was continuously repeatedfor a period of 3000 hours. Under these conditions, the yellowing index(YI) indicated that yellowing was minimal. Moreover, the coated samplesdid not show any visible signs of delamination.

[0057] The QUVB weathering device was outfitted with an FS40 lamp.Samples were disposed in the chamber of the device. The weathering cycleincluded exposure to the FS40 lamp for a period of 8 hours at 70° C.followed by 4 hours of dark time at 50° C. The weathering cycle wascontinuously repeated for a total time period of 3000 hours. Nodelamination was observed after exposure and yellowing was minimal.

[0058] The impact resistance was measured in accordance with ASTM D2794.The test was conducted on a 10 mil double wall polycarbonate sheet witha coating thickness of 8 microns. The results clearly show that the useof polyurethane in the coating composition maintains the impactresistance of the coated sample. Impact resistance was greater than160-200 pounds.

[0059] Advantageously, the coating compositions can be used to formfilms exhibiting excellent anti-fog and anti-condensation properties.Moreover, the coating compositions show fast drying behavior resultingin improved productivity cycles, use less solvent usage than prior artcompositions, show less degradation during extrusion, and maintainsufficient impact strength for use in numerous applications.

[0060] While the invention has been described with reference to anexemplary embodiment, it will be understood by those skilled in the artthat various changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the invention. Inaddition, many modifications may be made to adapt a particular situationor material to the teachings of the invention without departing from theessential scope thereof. Therefore, it is intended that the inventionnot be limited to the particular embodiment disclosed as the best modecontemplated for carrying out this invention, but that the inventionwill include all embodiments falling within the scope of the appendedclaims.

What is claimed is:
 1. A process for forming an anti-fog film on asubstrate comprising applying an aqueous coating composition to thesubstrate, wherein the aqueous coating composition comprises a siliconecompound free from a sulfonic acid group, a water dispersiblepolyurethane compound, and water; and coalescing the silicone compoundand polyurethane compound to form a film on the substrate wherein thesilicone compound is organosiloxane of the formula: M_(a)M′_(b)D_(c)D′_(d)T_(e)T′_(f)Q_(g), wherein the subscripts a, c, d, e, f,and g are zero or a positive integer, subject to the limitation that thesum of the subscripts b, d, and f is one or greater; M has the formula:R¹ ₃ SiO_(1/2), wherein each R¹ is independently a monovalenthydrocarbon radical having from one to forty carbon atoms; M′ has theformula: R² _(3-h) R³ _(h) SiO_(1/2), wherein each R² and R³ areindependently monovalent hydrocarbon radicals having from one to fortycarbon atoms, and the subscript h is 1, 2, or 3; D has the formula: R⁴ ₂SiO_(2/2), wherein each R⁴ is independently a monovalent hydrocarbonradical having from one to forty carbon atoms; D′ has the formula: R⁵_(2-i)R⁶ _(i)SiO_(2/2), wherein each of R⁵ and R⁶ is independently amonovalent hydrocarbon radical having from one to forty carbon atoms,and the subscript i is 1 or 2; T has the formula: R⁷SiO3/2, wherein eachR⁷ is a monovalent hydrocarbon radical having from one to forty carbonatoms; T′ has the formula: R⁸SiO_(3/2), wherein R⁸ is a monovalenthydrocarbon radical having from one to forty carbon atoms; and Q has theformula: SiO_(4/2); or an ionic or nonionic siloxane alkoxylate of theformula:

wherein each of R⁹⁻¹⁷ are independently a monovalent hydrocarbonradical, R¹⁸ is of the general formula:R¹⁹-Z-(C_(m)H_((2m-1))R²⁰O)_(j)(C_(n)H_(2n)O)_(k)R²¹, m and n areintegers greater than or equal to 0; j and k are integers greater thanor equal to 0, subject to the proviso that the sum of j+k is greaterthan or equal to 1; Z is —O—, —S—, —CO—, —NH—, or —NH₂—; R¹⁹ is adivalent hyrdocarbylene radical, R²⁰ and R²¹ are independently hydrogen,alkyl, hydroxyalkyl, amino, amido, amineoxide, cyano, isocyano, aryl,arylene, carboxy, alkoxy, halogen, haloalkyl, haloalkoxy, sulfo,sulfamo, phosphono, salts thereof, combinations comprising at least oneof the foregoing, and the like; and wherein x and y are integers greaterthan or equal to 0, subject to the proviso that x+y is greater than orequal to
 1. 2. The process according to claim 1, further comprisingheating the substrate to a temperature of about 20° C. to about 150° C.3. The process according to claim 1, wherein the substrate comprises apolyester, a cellulose ester, a polycarbonate, a polystyrene, apolyvinyl acetate, a polyolefin, and combinations comprising at leastone of the foregoing.
 4. The process according to claim 1, wherein theaqueous coating composition further comprises a co-solvent selected fromthe group consisting of N-methyl pyrrolidone, glycol ether, isopropanol,and combinations comprising at least one of the foregoing co-solvents.5. The process according to claim 1, wherein the silicone compound ischemically bound to the polyurethane compound.
 6. The process accordingto claim 1, wherein the co-solvent is about 5 to about 10 weight percentof the coating composition.
 7. The process according to claim 1, whereinthe silicone is a polydimethylsiloxane selected frompoly[dimethylsiloxane-co-methyl(3-hydroxypropyl)siloxane]graft-poly(ethyleneglycol) methyl ether,poly[dimethylsiloxane-co-[3-[2-(2-hydroxyethoxy)ethoxy]propyl]methylsiloxane,poly[dimethylsiloxane-co-(3-aminopropyl)methylsiloxane],poly[dimethylsiloxane-co-methyl(3-hydroxypropyl)siloxane]-graftpoly(ethylene/propylene glycol) methyl ether,poly[dimethylsiloxane-co-methyl(3-hydroxypropyl)siloxane]-graft-tetrakis(1,2-butyleneglycol), poly(dimethylsiloxane-co-alkylmethylsiloxane),poly[dimethylsiloxane-co-methyl(stearoyloxyalkyl)siloxane],poly[dimethylsiloxane-co-methyl(3-hydroxypropyl)siloxane]-graft-poly(ethylene/propyleneglycol),poly[dimethylsiloxane-co-methyl(3-hydroxypropyl)siloxane]-graft-poly(ethyleneglycol) [3-(trimethylammonio)propyl chloride,poly[dimethylsiloxane-co-methyl(3-hydroxypropyl)siloxane]graft-poly(ethyleneglycol) 3-aminopropyl ether,poly[dimethylsiloxane-co-methyl(3,3,3-trifluoropropyl)siloxane],poly(dimethylsiloxane bis[[3-[(2-aminoethyl)amino]propyl]dimethoxysilyl]ether, and poly(dimethylsiloxane) ethoxylate/propoxylated.
 8. A processfor forming an anti-fog film, the process comprising: applying a coatingcomposition to a substrate, wherein the coating composition comprises asilicone compound free from a sulfonic acid functional group, anisocyanate, a polyol and a catalyst; and crosslinking the coatingcomposition to form the anti-fog film, wherein the crosslinkingcomprises heating the substrate to a temperature and for a timeeffective to form the film.
 9. The process according to claim 8, whereinthe silicone compound is of the formula: M_(a)M′_(b)D_(c)D′_(d)T_(e)T′_(f)Q_(g), wherein the subscripts a, c, d, e, f,and g are zero or a positive integer, subject to the limitation that thesum of the subscripts b, d, and f is one or greater; M has the formula:R¹ ₃ SiO_(1/2), wherein each R¹ is independently a monovalenthydrocarbon radical having from one to forty carbon atoms; M′ has theformula: R² _(3-h) R³ _(h) SiO_(1/2), wherein each R² and R³ areindependently monovalent hydrocarbon radicals having from one to fortycarbon atoms, and the subscript h is 1, 2, or 3; D has the formula: R⁴ ₂SiO_(2/2), wherein each R⁴ is independently a monovalent hydrocarbonradical having from one to forty carbon atoms; D′ has the formula: R⁵_(2-i)R⁶ _(i)SiO_(2/2), wherein each of R⁵ and R⁶ is independently amonovalent hydrocarbon radical having from one to forty carbon atoms,and the subscript i is 1 or 2; T has the formula: R⁷SiO_(3/2), whereineach R⁷ is a monovalent hydrocarbon radical having from one to fortycarbon atoms; T′ has the formula: R⁸SiO_(3/2), wherein R⁸ is amonovalent hydrocarbon radical having from one to forty carbon atoms;and Q has the formula: SiO_(4/2).
 10. The process according to claim 8,wherein the silicone compound is an ionic or nonionic siloxanealkoxylate of the formula:

wherein each of R⁹⁻¹⁷ are independently a monovalent hydrocarbonradical, R¹⁸ is of the general formula: R¹⁹-Z-(C_(m)H_((2m-1))R²⁰O)_(j)(C_(n)H_(2n)O)_(k) R²¹, m and n are integers greater than or equal to 0;j and k are integers greater than or equal to 0, subject to the provisothat the sum of j+k is greater than or equal to 1; Z is H, —O—, —S—,—SH—, —CO—, —NH—, or —NH₂—; R¹⁹ is a divalent hyrdocarbylene radical,R²⁰ and R²¹ are independently hydrogen, alkyl, hydroxyalkyl, amino,amido, amineoxide, cyano, isocyano, aryl, arylene, carboxy, alkoxy,halogen, haloalkyl, haloalkoxy, sulfo, sulfamo, phosphono, saltsthereof, combinations comprising at least one of the foregoing, and thelike; and wherein x and y are integers greater than or equal to 0,subject to the proviso that x+y is greater than or equal to
 1. 11. Theprocess according to claim 8, wherein crosslinking the coatingcomposition to form the anti-fog film comprises heating the substrate toa temperature of about 20° C. to about 150° C.
 12. The process accordingto claim 8, wherein the substrate comprises a polyester, a celluloseester, a polycarbonate, a polystyrene, a polyvinyl acetate, apolyolefin, and combinations comprising at least one of the foregoing.13. The process according to claim 8, wherein the polyol comprises apolycarbonate polyol.
 14. The process according to claim 8, wherein thecatalyst comprises a metal acetyl acetonate.
 15. The process accordingto claim 8, wherein the catalyst is selected frombis(2,4-pentanedionate) nickel (II), diacetonitrilediacetylacetonatonickel, diphenylnitrilediacetylacetonato nickel, andbis(triphenylphosphine)diacetyl acetylacetonato nickel.
 16. The processaccording to claim 8, wherein the coating composition further comprisesa co-solvent.
 17. A glass or plastic article having an anti-foggingsurface comprising: a glass or plastic substrate; and an anti-fogcoating disposed on at least one surface of the substrate, the anti-fogcoating comprising a crosslinked film formed from a silicone, anisocyanate, a polyol and a catalyst.
 18. The glass or plastic article ofclaim 17, wherein the silicone compound is of the formula: M_(a)M′_(b)D_(c)D′_(d)T_(e)T′_(f)Q_(g), wherein the subscripts a, c, d, e, f,and g are zero or a positive integer, subject to the limitation that thesum of the subscripts b, d, and f is one or greater; M has the formula:R¹ ₃ SiO_(1/2), wherein each R¹ is independently a monovalenthydrocarbon radical having from one to forty carbon atoms; M′ has theformula: R² _(3-h) R³ _(h) SiO_(1/2), wherein each R² and R³ areindependently monovalent hydrocarbon radicals having from one to fortycarbon atoms, and the subscript h is 1, 2, or 3; D has the formula: R⁴ ₂SiO_(2/2), wherein each R⁴ is independently a monovalent hydrocarbonradical having from one to forty carbon atoms; D′ has the formula: R⁵_(2-i)R⁶ _(i)SiO_(2/2), wherein each of R⁵ and R⁶ is independently amonovalent hydrocarbon radical having from one to forty carbon atoms,and the subscript i is 1 or 2; T has the formula: R⁷SiO3/2, wherein eachR⁷ is a monovalent hydrocarbon radical having from one to forty carbonatoms; T′ has the formula: R⁸SiO_(3/2), wherein R⁸ is a monovalenthydrocarbon radical having from one to forty carbon atoms; and Q has theformula: SiO_(4/2).
 19. The glass or plastic article of claim 17,wherein the silicone compound is an ionic or nonionic siloxanealkoxylate of the formula:

wherein each of R⁹⁻¹⁷ are independently a monovalent hydrocarbonradical, R¹⁸ is of the general formula: R¹⁹-Z-(C_(m)H_((2m-1))R²⁰O)_(j)(C_(n)H_(2n)O)_(k) R²¹, m and n are integers greater than or equal to 0;j and k are integers greater than or equal to 0, subject to the provisothat the sum of j+k is greater than or equal to 1; Z is —O—, —S—, —CO—,—NH—, or —NH₂—; R¹⁹ is a divalent hyrdocarbylene radical, R²⁰ and R²¹are independently hydrogen, alkyl, hydroxyalkyl, amino, amido,amineoxide, cyano, isocyano, aryl, arylene, carboxy, alkoxy, halogen,haloalkyl, haloalkoxy, sulfo, sulfamo, phosphono, salts thereof,combinations comprising at least one of the foregoing, and the like; andwherein x and y are integers greater than or equal to 0, subject to theproviso that x+y is greater than or equal to
 1. 20. The glass or plasticarticle of claim 17, wherein the polyol comprises a polycarbonatepolyol.
 21. The glass or plastic article of claim 17, wherein thecatalyst comprises a metal acetyl acetonate.
 22. The glass or plasticarticle of claim 17, wherein the catalyst is selected frombis(2,4-pentanedionate) nickel (II), diacetonitrilediacetylacetonatonickel, diphenylnitrilediacetylacetonato nickel, andbis(triphenylphosphine)diacetyl acetylacetonato nickel.